Alignment device for a prosthetic limb

ABSTRACT

An alignment device ( 10 ) for a prosthetic limb ( 12 ) to provide angular movement of the prosthetic limb ( 12 ) in an anterior-posterior plane. The alignment device ( 10 ) includes a mounting mechanism ( 24 ) supported by a prosthetic socket ( 28 ), a prosthetic limb ( 12 ) operatively connected to the mounting mechanism ( 24 ), and an extendable and retractable positioning mechanism ( 84 ) operatively connected to the mounting mechanism ( 24 ) and the prosthetic limb ( 12 ). The prosthetic limb ( 12 ) is adapted to move angularly in the anterior-posterior plane upon extension or retraction of the positioning mechanism ( 84 ). A hinge connection ( 606, 610 ) may be provided between the prosthetic limb ( 12 ) and the mounting mechanism ( 602 ) to permit the prosthetic limb ( 12 ) to rotate about a hinge axis extending through the hinge connection ( 606, 610 ). Methods for aligning a prosthetic limb are also disclosed.

CROSS-REFERENCE

The present application is a continuation-in-part of my copendingapplication U.S. Ser. No. 09/199,240, filed on Nov. 24, 1998, now U.S.Pat. No. 6,206,932, the disclosure of which is hereby incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to prosthetic devices and, moreparticularly, to an alignment device for providing angular adjustment ofa prosthetic limb in forward and rearward directions to obtain acustomized fit for the wearer.

BACKGROUND OF THE INVENTION

Various devices have been developed to provide alignment for prostheticlimbs, such as a prosthetic lower leg worn by a below-the-knee amputee.The limb is typically adjustably attached to a prosthetic knee socketfor providing a rigid leg support. The alignment devices are designed topermit angular adjustment of the limb in a forward-rearward plane belowthe prosthetic knee socket to approximate the proper toe-to-heel pitchand gait for the wearer. Proper fit of the prosthetic limb is necessaryfor the full range of motion and activity of the wearer to avoidundesirable health risks, particularly in diabetic amputees that aresusceptible to irritation in areas on and around the residual limbcommon to amputees. This irritation primarily results from improperloading on the rigid prosthetic knee socket that causes excessivepressure in areas of the residual limb.

In the past, alignment devices have been designed that mount between alower end of a prosthetic socket and an upper end of a prosthetic limb.The prosthetic limb may include a leg portion and a leaf-spring footportion. In general, the leg and foot portions of the prosthetic limbare rigid members, although some elastic energy absorbing members may beprovided to help absorb shock as the wearer goes through conventionalmotions.

In one known alignment approach for prosthetic limbs, such as those ofthe laminated plate-type as disclosed in U.S. Pat. Nos. 4,547,913 and4,822,363, the limb is attached to a mounting flange extendingdownwardly from the prosthetic knee socket. A prosthetist angularlyaligns the limb in forward and rearward directions by inserting variousangled wedge or shim adaptors between an upper end of the limb and alower end of the mounting flange. Shim adaptors of varying angles aretested by the prosthetist until one providing the most favorabletoe-to-heel pitch and gait for the wearer is identified.

In another known alignment approach, the prosthetic limb is connected tothe prosthetic socket through a rotational joint, such as a rotatablesocket adaptor or pair of sliding curved plates. During the customfitting process, the prosthetist rotationally adjusts and aligns theprosthetic limb relative to the knee socket to the desired angularposition for proper toe-to-heel pitch and gait. Typically, the alignmentprocedure requires multiple adjustments to the alignment device withadjustment tools.

In each of the alignment approaches described above, the wearer may berestricted to the toe-to-heel pitch set by the prosthetist after thecustom fitting process, and the wearer may have limited ability toreadily adjust the angular setting of the limb as may be desired,particularly when changing between shoes of different heel height. Whenthe wearer does attempt to make an alignment adjustment, that adjustmentmay affect other adjustments already set on the prosthetic limb, therebyadding to the complexity of the adjustment process. To avoid makingcomplex manual adjustments to the alignment device for accommodatingshoes of different height, the wearer may insert padding, shims or otheradjustment devices into the shoes which improves the fit but may notachieve the optimum toe-to-heel pitch and gait for the particular shoe.Alternatively, the wearer may simply decide to wear shoes of only oneheel height.

Thus, there is a need for a prosthetic limb alignment device that isreadily manually adjustable by the wearer to optimize the toe-to-heelpitch and gait of the wearer.

There is also a need for a prosthetic limb alignment device that isreadily manually adjustable by the wearer to accommodate for shoes ofdifferent heel heights while providing the optimum toe-to-heel pitch andgait for the wearer.

There is yet another need for a prosthetic limb alignment device thatmay be readily manually adjusted by the wearer without requiringadjustment tools.

There is yet also a need for a prosthetic limb adjustment device that isreadily manually adjustable without affecting other adjustments set onthe prosthetic limb.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing and other shortcomings anddrawbacks of alignment devices and methods heretofore known. While theinvention will be described in connection with certain embodiments, itwill be understood that the invention is not limited to theseembodiments. On the contrary, the invention includes all alternatives,modifications and equivalents as may be included within the spirit andscope of the present invention.

In accordance with the principles of the present invention, an alignmentdevice and method are provided for aligning a prosthetic limb worn by anamputee. The alignment device may be used in a below-the-knee amputationenvironment wherein it is mounted between a lower end of a prostheticsocket and an upper end of a prosthetic limb. The alignment device isparticularly designed to provide angular alignment of the prostheticlimb in forward and rearward directions below the knee socket tooptimize the toe-to-heel pitch and gait for the wearer as shoes ofdifferent height are worn. Other adjustments of the prosthetic limbrelative to the prosthetic knee socket are also possible with thealignment device of the present invention.

The alignment device includes a mounting mechanism that is adapted to beaffixed to a prosthetic knee socket, mechanical knee or other prostheticdevice. A prosthetic limb is operatively connected to the mountingmechanism and is adapted to move in forward and rearward directions inan anterior-posterior plane upon adjustment of the alignment device. Anextendable and retractable positioning mechanism is operativelyconnected to the mounting mechanism and the prosthetic limb. Theprosthetic limb is angularly aligned in the anterior-posterior planeupon extension and retraction of the positioning mechanism. Thepositioning mechanism may include a manually adjustable turnbuckleassembly, hydraulic actuator, electric actuator or other adjustmentdevice that is readily accessible on the alignment device to permitadjustments by the wearer.

The alignment device of the present invention is intended to give thewearer more control and adaptability over the types of shoes that may beworn. The alignment device of the present invention provides the abilityto change the loading on the knee socket in such a way that it providesless irritation to areas on or around the residual limb common toamputees. Moreover, the alignment device of the present invention givesthe wearer a readily adjustable heel-to-toe configuration withoutdisturbing any other fixed adjustments on the prosthetic limb, andwithout requiring adjustment tools.

The above and other objects and advantages of the present inventionshall be made apparent from the accompanying drawings and thedescription thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description of the embodiments given below, serve toexplain the principles of the invention.

FIG. 1 is a perspective view of an alignment device for a prostheticlimb in accordance with one embodiment of the present invention,illustrating a turnbuckle assembly as a positioning mechanism in thealignment device;

FIG. 2 is a side view, partially in cross-section, of the alignmentdevice and prosthetic limb illustrated in FIG. 1;

FIG. 3 is a view similar to FIG. 2 illustrating angular alignment of theprosthetic limb in an anterior-posterior plane upon actuation of thepositioning mechanism;

FIG. 4 is a partial front view of the alignment device illustrated inFIG. 1;

FIG. 5 is a partial side view taken on lines 5—5 of FIG. 4 of analignment device for a prosthetic limb in accordance with a secondembodiment of the present invention, illustrating a hydraulic actuatoras a positioning mechanism in the alignment device;

FIG. 5A is a view similar to FIG. 5 of an alignment device for aprosthetic limb in accordance with a third embodiment of the presentinvention, illustrating an electric actuator as a positioning mechanismin the alignment device;

FIG. 6 is a partial cross-sectional view of an alignment device for aprosthetic limb in accordance with a fourth embodiment of the presentinvention, illustrating a linkage assembly as a positioning mechanism inthe alignment device;

FIG. 7 is a cross-sectional view taken along line 7—7 of FIG. 6illustrating a slidable mount for the alignment device of the presentinvention;

FIG. 8 is view similar to FIG. 6 of an alignment device for a prostheticlimb in accordance with a fifth embodiment of the present invention,illustrating a linkage assembly as a positioning mechanism in thealignment device;

FIG. 9 is a cross-sectional view taken along line 9—9 of FIG. 8;

FIG. 10 is view similar to FIG. 2 of an alignment device for aprosthetic limb in accordance with a sixth embodiment of the presentinvention, illustrating a turnbuckle assembly as a positioning mechanismin the alignment device;

FIG. 11 is a view similar to FIG. 6 of an alignment device for aprosthetic limb in accordance with a seventh embodiment of the presentinvention, illustrating a linkage assembly as a positioning mechanism inthe alignment device;

FIG. 12 is a partial perspective view of an alignment device for aprosthetic limb in accordance with an eighth embodiment of the presentinvention, illustrating a linkage assembly as a positioning mechanism inthe alignment device;

FIG. 13 is a cross-sectional view taken along line 13—13 of FIG. 12;

FIG. 13A is an enlarged view of the linkage assembly illustrated in FIG.13 in a locked position;

FIG. 13B is a view similar to FIG. 13A illustrating the linkage assemblyin an unlocked position;

FIG. 14 is a view similar to FIG. 6 of an alignment device for aprosthetic limb in accordance with a ninth embodiment of the presentinvention, illustrating a linkage assembly as a positioning mechanism inthe alignment device; and

FIG. 15 is a cross-sectional view taken along line 15—15 of FIG. 14.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

With reference to the figures, and to FIGS. 1-4 in particular, oneembodiment of an alignment device 10 for a prosthetic limb 12 is shownin accordance with the principles of the present invention. As will bedescribed in greater detail below, alignment device 10 is particularlyadapted to provide angular alignment of the prosthetic limb 12 in ananterior-posterior plane defined by axis “A” (FIG. 1) to optimize thetoe-to-heel pitch and gait of the wearer as different shoes 14, 16(FIGS. 2 and 3) with varying heel heights are worn.

As illustrated and described herein, prosthetic limb 12 may be alaminated plate-type prosthetic device similar to the lower limbprosthetic device sold under the trademark Flex Foot and described inU.S. Pat. Nos. 4,547,913 and 4,822,363 to Phillips, each disclosure ofwhich is incorporated herein by reference in its entirety, althoughother types of prosthetic devices are also contemplated. A prostheticfoot 18, such as a leaf-spring foot 19 (FIG. 10) covered with a footshell 20 (FIGS. 1-3), is connected to a lower end of the prosthetic limb12. A shell cover 22 (shown in phantom in FIG. 1) that simulates themuscle tone of the wearer may be mounted about the prosthetic limb 12 asis well known in the art. While the present invention will be describedherein in a below-the-knee amputation environment, those of ordinaryskill in the art will readily appreciate the application of the presentinvention in combination with artificial or mechanical knees and othertypes of prosthetic devices without departing from the spirit and scopeof the present invention.

Alignment device 10 includes a mounting base 24 that may be supported bya mounting adaptor 26 through a set of vertically aligned fasteners (notshown) that extend upwardly through the mounted base 24 and connect tothe mounting adaptor 26. Alternatively, the mounting base 24 may beformed integrally with mounting adaptor 26. Mounting adaptor 26 may be aconcave or cup-shaped support made from thermoset or thermoform plasticthat is adapted to be connected to a conventional prosthetic socket 28(FIGS. 2 and 3) as is well known in the art, with the alignment device10 positioned below the prosthetic socket 28. A pair of side plates 30are mounted on either side of the mounting base 24 through a pair offasteners 32 a, 32 b that extend across the width of the mounting base24 and through the side plates 30.

As best understood with reference to FIGS. 2 and 3, a generally L-shapedlinkage or lever 34 is pivotally mounted to one of the fasteners 32 bfor pivotal rotation about the fastener 32 b in a plane defined by axis“A” (FIG. 1), as illustrated by arrow 36 in FIG. 2. The lever 34 isadapted to rotate about a hinge axis 35 defined by the fastener 32 b.The lever 34 may terminate in a pair of U-shaped ends 38 and 40. Themounting base 24 has a recess 42 (FIGS. 2-4) for receiving the lever 34.A prosthetic limb support mechanism 44, such as a U-shaped clamp asillustrated in the figures, is mounted on an upper end of the prostheticlimb 12 through a pair of fasteners 46 that extend through legs 48 ofthe support mechanism 44 and the thickness of limb 12. Support mechanism44 includes a hinge connection 50 that is pivotally connected to leverend 38 through a hinge pin 52 that extends through the hinge connection50 and the lever end 38. The hinge connection 50 of support mechanism 44is adapted to rotate about a hinge axis 54 defined by the hinge pin 52.

Prior to mounting the prosthetic limb 12 in support mechanism 44 throughfasteners 46, the limb 12 is cut to an appropriate length for theparticular wearer. During the fitting process, the prosthetic limb 12may be moved laterally in the support mechanism 44 before final assemblyto provide lateral adjustment of the limb 12 in the medial-lateral planedefined by axis “B” (FIG. 1). The prosthetic limb 12 may additionally berotated in the medial-lateral plane during the fitting process to adjustthe abduction-adduction angle of the limb 12 for a custom fit.

Further referring to FIGS. 1-4, a prosthetic limb receiving member 56 isrotatably mounted between the side plates 30. A pair of fasteners 58 arethreadedly engaged in bores 59 in the ends 60 of receiving member 56.The ends 60 of the receiving member 56 are located in bushings 62 (FIG.4), for example, nylon bushings, that extend through bores 64 formed ata lower end of the side plates 30. Inner ends 66 of the nylon bearings62 engage ends 60 of the rotatable member 56, while outer ends 68 of thebearings 62 are clamped between washers 70 and an outer wall 72 of theside plates 30. Set screws 61 are also threadedly engaged in bores 59below the fasteners 58.

As best understood with reference to FIGS. 2-4, the rotatable member 56includes an opening 74 extending through the member 56 for slidablyreceiving the prosthetic limb 12. Set screws 76 extend into the opening74, and may include bearing tips 78 (FIG. 6), for example, nylon tips,that engage front and rear surfaces 80 a, 80 b of the prosthetic limb 12to permit sliding movement of the limb 12 relative to the rotatablemember 56. The set screws 76 are provided to prevent fore and aftmovement of the prosthetic limb 12 in the opening 74. The set screws 59may also include tips 82 (FIG. 4), for example, nylon tips, to permitsliding movement of the limb 12 relative to the rotatable member 56while preventing lateral movement of limb 12 within the opening 74. Itwill be appreciated by those of ordinary skill in the art that otherbearing structures are possible for permitting relative movement of thelimb 12 and the rotatable member 56 without departing from the spiritand scope of the present invention. For example, one or more nylonbearing blocks or plates (not shown) may be provided within the opening74 to slidably engage the prosthetic limb 12.

An expandable and retractable positioning mechanism or linkage 84, suchas a turnbuckle assembly 86, includes hinge connections 88 a, 88 bformed at opposite ends the assembly 86. The upper hinge connection 88 aof turnbuckle assembly 86 is pivotally connected to the lever end 40through a pin 90, while the lower hinge connection 88 b of turnbuckleassembly 86 is pivotally connected to an arm 92, which may be U-shaped,and extends outwardly from the rotatable limb receiving member 56through a pin 94.

As those of ordinary skill in the art will readily appreciate, theturnbuckle assembly 86 is easily accessible for manual actuation by thewearer. As shown in FIG. 2, as turnbuckle wheel 96 is manually rotatedin one direction, as represented by arrow 98, the turnbuckle assembly 86retracts in a generally linear direction which simultaneously rotateslever 34 in a clockwise direction, as represented by arrow 36, and limbreceiving member 56 in a counterclockwise direction, as represented byarrow 102. During retraction of turnbuckle assembly 56, the clockwiserotation of lever 34 moves the hinge connection 50 of limb supportmechanism 44 in a clockwise direction as shown in FIG. 2 which resultsin a forward angular movement of the prosthetic limb 12 in theanterior-posterior plane, as represented by arrow 104. During thismovement, the prosthetic limb 12 rotates generally about a horizontalaxis defined by the limb receiving member 56. As the hinge connection 50moves in the clockwise direction and the limb receiving member 56rotates in a counterclockwise direction to provide angular movement ofprosthetic limb 12 in the forward direction, the prosthetic limb 12slides upwardly through the opening 74 formed in the rotatable limbreceiving member 56. Movement of the prosthetic limb 12 in the forwarddirection may be desirable to accommodate a flat or low heel shoe, suchas shoe 14 of FIG. 2.

As shown in FIG. 3, the heeled shoe 16 may require angular adjustment ofthe prosthetic limb 12 in a rearward direction in the anterior-posteriorplane to optimize the toe-to-heel pitch and gait for the wearer. Toaccomplish the desired angular movement of limb 12, the turnbuckle wheel96 is manually rotated in an opposite direction to that shown in FIG. 2,as represented by arrow 106. The turnbuckle assembly 86 extends in agenerally linear direction which simultaneously rotates lever 34 in acounterclockwise direction, as represented by arrow 108, and limbreceiving member 56 in a clockwise direction, as represented by arrow110. During extension of turnbuckle assembly 86, the counterclockwiserotation of lever 34 moves the hinge connection 50 of limb supportmechanism 44 in a counterclockwise direction as shown in FIG. 3 whichresults in a rearward angular movement of the prosthetic limb 12 in theanterior-posterior plane, as represented by angle “a”. It will beappreciated that as the hinge connection 50 moves in thecounterclockwise direction and limb receiving member 56 moves in aclockwise direction to provide angular movement of prosthetic limb 12 inthe rearward direction, the prosthetic limb 12 slides downwardly throughthe opening 74 formed in the rotatable limb receiving member 56. It willalso be appreciated that as the prosthetic limb 12 is moved in forwardand rearward angular movements, the rotatable limb receiving member 56acts as a general hinge or fulcrum about which the prosthetic limb 12rotates during the forward and rearward angular adjustments. In thisway, the prosthetic foot 18 is advantageously maintained generally belowthe prosthetic socket 28 during the full range of motion of thealignment device 10.

As shown in FIG. 5, an alignment device 200 in accordance with analternative embodiment of the present invention is illustrated forproviding angular alignment of prosthetic limb 12, where like referencenumerals are used to identify like parts. In this embodiment, theturnbuckle assembly 86 of FIGS. 1-4 is replaced with an extensible andretractable hydraulic actuator 202 that includes hinge connections 204a, 204 b formed at opposite ends of the actuator 202. One hingeconnection 204 a is connected to a moveable end of piston rod 206 androtatably connected to lever end 40, while the other hinge connection204 b extends outwardly from an opposite end of actuator housing 208 andis rotatably connected to connection 92 of rotatable limb receivingmember 56. The actuator 202 is filled with hydraulic fluid that is freeto port to opposite sides of piston head 210 through fluid lines 212 anda manually actuatable switch 214. While the switch 214 is manuallydepressed, the wearer is able to manually adjust the angular position ofthe prosthetic limb 12, as represented by arrows 215. When the desiredangular position of limb 12 is achieved, the switch 214 may be releasedto set the limb 12 in the desired adjusted angular position. Switch 214may be mounted on one of the side plates 30 or any other suitable area.

Alternatively, an alignment device 300 in accordance with anotherembodiment of the present invention is shown in FIG. 5A, where likereference numerals represent like parts. In this embodiment, theturnbuckle assembly 86 of FIGS. 1-4, and the hydraulic actuator 202 ofFIG. 5, may be replaced with an extendable and retractable electricactuator 302. Actuator 302 includes hinge connections 304 a, 304 bformed at opposite ends of the actuator wherein one hinge connection 304a is connected to a moveable threaded shaft 306 and rotatably connectedto lever end 40, while the other hinge connection 304 b extendsoutwardly from an opposite end of actuator housing 308 and is rotatablyconnected to connection 92 of rotatable limb receiving member 56. Theactuator 302 includes a reversible electric motor 310 coupled to a powersource (not shown) and manually actuatable switch (not shown) throughelectrical leads 312, and a planetary gear drive 314 connected to amechanical output of the electric motor 310. The planetary gear drive314 is connected to a threaded collar 316 that rotates when the motor310 is energized upon actuation of a switch (not shown) coupled to themotor. A bearing 318 is provided within the actuator housing 308 topermit rotation of the collar 316 within the housing. It will beappreciated that rotation of the threaded collar 316 in oppositedirections, as represented by arrows 320, retracts or extends themoveable threaded shaft 306 relative to the actuator housing 308. Anactuatable wheel 322 is connected to the threaded collar 316 to permitmanual rotation of the collar 316 as desired to retract or extend themoveable threaded shaft 306.

As shown in FIGS. 6-7, an alternative embodiment of an alignment device400 in accordance with the principles of the present invention is shown,where like reference numerals are used to identify like parts. Alignmentdevice 400 includes a mounting base 402 that is slidably mounted tomounting adaptor 26 through an adjustable mount 404. Adjustable mount404 is connected to mounting adaptor 26 through a set of verticallyaligned fasteners 406 that extend upwardly through the adjustable mount404 and connect to the mounting adaptor 26. As shown in FIG. 7, a lowerend of adjustable mount 404 may include an elongated dovetail groove 408that extends generally parallel to the anterior-posterior plane. Anupper end of the mounting base 402 may include a dovetail tongue 410that cooperates with the dovetail groove 408 formed in the mountingadaptor 26. With this arrangement, the position of the alignment device400 may be adjusted in forward and rearward directions relative to themounting adaptor 26, as represented by arrows 412 (FIG. 6), to adjustthe toe pressure exerted on the prosthetic foot 18 (FIG. 1) of thewearer. After the desired forward or rearward adjustment of alignmentdevice 400 is achieved, the mounting base 402 is fixed to the adjustablemount 404 through a set of horizontally aligned set screws 414 thatextend through bores 416 (FIG. 7) formed in the adjustable mount 404 andengage the dovetail tongue 410 of the mounting base 402. While adovetail mounting arrangement is shown, those of ordinary skill in theart will appreciate that other structural formations and configurationof components is possible without departing from the spirit and scope ofthe present invention.

With further reference to FIGS. 6-7, an extendable and retractablepositioning mechanism 418, arranged as a linkage assembly, is providedto move the prosthetic limb 12 through the forward and rearward angularmovements described in detail above. The positioning mechanism 418includes a threaded screw 420 rotatably connected to a pair of flanges422 of the alignment device 400. The threaded screw 420 extends acrossthe length of the mounting base 402 and is aligned generally parallel tothe anterior-posterior plane. A pair of spaced guide pins (not shown)are also connected to the pair of flanges 422 and extend across thelength of the alignment device 400 on opposite sides of the threadedscrew 420.

As best understood with reference to FIG. 6, a generally T-shapedcoupling member 424 is threadably connected to the threaded screw 420for extended and retracted movement along the screw 420 upon manualrotation of actuation wheel 426. A nylon bearing plate 427 is mountedbetween the coupling member 424 and the mounting base 402 to permitrelative movement between the components. Coupling member 424 includes apair of unthreaded bores (not shown) that slidably receive the pair ofguide pins (not shown). The coupling member 424 includes a hingeconnection 428, which may be U-shaped, and is rotatably connected withthe hinge connection 50 formed on an upper end of the limb supportmechanism 44 through a pin 430. Those of ordinary skill in the art willreadily appreciate that as the adjustment wheel 426 is rotated inopposite directions, the coupling member 424 will be extended orretracted on the threaded screw shaft 420, as represented by arrows 432(FIG. 6) to angularly align the prosthetic limb 12 as discussed indetail above. The rotatable limb receiving member 56 permits theprosthetic limb 12 to slide through the opening 74 during the adjustmentprocess.

An electric actuator 434, for example, a motor and planetary gear drive,may be mounted to one of the flanges 422 for rotating the actuationwheel 426 when the motor (not shown) within the actuator 434 isenergized. A spindle 436 is connected to the actuator 434 and includesan elastomeric O-ring 438 positioned about one end of the spindle 436.The O-ring 438 is adapted to engage a surface 440 of the actuation wheel426 for rotating the wheel 426 when the motor (not shown) is energized.When the electric actuator 434 is not used, an optional filler piece(not shown) is inserted in the motor receiving bore 442 formed in one ofthe flanges 422.

Referring now to FIGS. 8-9, an alignment device 500 in accordance withan alternative embodiment of the present invention is illustrated wherelike reference numerals are used to identify like parts. In thisembodiment, an extendable and retractable positioning mechanism 502,arranged as a linkage assembly, is provided to move the prosthetic limb12 through forward and rearward angular movements. The positioningmechanism 500 includes a threaded screw 504 that is pivotally mounted ina rotatable pin 506. Pin 506 is rotatably connected to a hingeconnection 508, which may be U-shape, and hinge connection 508 isintegral with mounting base 510. Screw 504 includes an unthreaded shankportion 512 extending through an unthreaded bore 514 formed in therotatable pin 506. Stop collars 516 are mounted on screw 504 on oppositesides of pin 506 to prevent lateral movement of the screw 504. Thethreaded screw 504 extends across the length of the adjustment device500 and is aligned generally parallel to the anterior-posterior plane.

As best understood with reference to FIGS. 8 and 9, a coupling member518, in the form of a rotatable pin, is connected to the threaded screw504 through a threaded bore 520 for extended and retracted movementalong the screw 504 upon manual rotation of actuation wheel 522. Limbsupport mechanism 524 includes a hinge connection 526, which may beU-shaped, for rotatably supporting the coupling member 518 in a pair ofnylon bushings 528 inserted into upstanding legs 530 of the supportmechanism 524. A stop collar 531 is affixed to the free end of threadedscrew 504 to prevent the coupling member 518 from moving off the end ofscrew 504.

As best understood with reference to FIG. 8, a limb receiving member 532is rotatably supported between the pair of side plates 30 (one shown).In this embodiment, the prosthetic limb 12 is received in an opening 534formed in the rotatable member 532, and a pair of fasteners 536 (oneshown) extend through the rotatable member 532 and the thickness of thelimb 12 to rigidly fix the limb 12 in the rotatable member 532. It willbe appreciated that as the coupling member 518 is extended and retractedon threaded screw 504, as represented by arrows 538 (FIG. 8), thethreaded screw 504, pin 506, coupling member 518 and limb receivingmember 532 rotate to permit the desired forward or rearward angularalignment of the prosthetic limb 12.

With reference now to FIG. 10, an alternative embodiment of an alignmentdevice, designated at numeral 600, is shown in accordance with theprinciples of the present invention. In this embodiment, alignmentdevice 600 includes a mounting mechanism 602 that is mounted to amounting adaptor 604. The mounting mechanism 602 includes a hingeconnection 606, which may be U-shaped, and thus, hinge mechanism 602 isrotatably connected to the hinge connection 50 formed on the upper endof the limb support mechanism 44 through a pin 608. A hinge connection610, which may be U-shaped, is mounted to the prosthetic limb 12 througha pair of fasteners 612.

An expandable and retractable positioning mechanism or linkage 614, suchas turnbuckle assembly 86, includes hinge connections 616 a, 616 bformed at opposite ends the turnbuckle assembly 86. The upper hingeconnection 616 a of turnbuckle assembly 86 is pivotally connected to ahinge connection 618, which may be U-shaped. Hinge connection 618 ismounted to mounting adaptor 604. A pin 620 extends through the hingeconnections 616 a and 618 to permit rotation of hinge connection 616 arelative to the fixed hinge connection 618. Lower hinge connection 616 bis rotatably connected to hinge connection 610. It will be appreciatedthat rotation of manually actuatable wheel 622 in opposite directionswill retract or extend the turnbuckle assembly 86 as discussed in detailabove to cause the prosthetic limb 12 to move in forward and rearwardangular movements through rotation of the limb 12 about pin 608. Whileturnbuckle assembly 86 is shown, it will be appreciated that thehydraulic actuator 202 or electric actuator 302 may be used as well.

Referring now to FIG. 11, an alignment device 700 in accordance with analternative embodiment of the present invention is illustrated. Anextendable and retractable positioning mechanism 702, arranged as alinkage assembly, is provided to move the prosthetic limb 12 throughforward and rearward angular movements as desired by the wearer. Thepositioning mechanism 702 includes a shaft 704 connected to a pair offlanges 706 of a mounting base 708. The shaft 704 extends across thelength of the mounting base 708 and is aligned generally parallel to theanterior-posterior plane.

A generally T-shaped coupling member 710 is slidably mounted on theshaft 704 for extended and retracted movement along the shaft. A pair ofspaced guide pins (not shown) are also connected to the pair of flanges706 and extend across the length of alignment device 700 on oppositesides of the shaft 704. A nylon bearing plate 712 is mounted between thecoupling member 710 and the mounting base 708 to permit relativemovement between the components. Coupling member 710 includes threeunthreaded bores 713 (one shown) that slidably receive shaft 704 and thepair of guide pins (not shown). Coupling member 710 includes a hingeconnection 714 which may be U-shaped, and thus, coupling member 710 isrotatably connected with the hinge connection 50 formed on an upper endof the limb support mechanism 44 through a pin 716. A pair ofselectively inflatable pneumatic bladders 718 are positioned on oppositesides of the limb 12 between the flanges 706 and the limb supportmechanism 44. The bladders 718 may be held in place by a threadedfastener (not shown) extending through the support mechanism 44 andterminating in the bladders 718. The bladders 718 are manuallyinflatable and deflatable through valve stems 720 which are also used tosupport the bladders on their outer ends. Alternatively, the bladders718 may receive hydraulic fluid, in which case a manually actuatableswitch (not shown), such as switch 214 of FIG. 5, may be incorporated topermit porting of hydraulic fluid between the pair of bladders 718.Those of ordinary skill in the art will readily appreciate that as eachbladder 718 is selectively inflated or deflated through valve stems 720,the coupling member 710 will be extended or retracted on the shaft 704to angularly align the prosthetic limb 12 as discussed in detail above.The rotatable limb receiving member 56 (FIG. 1) permits the prostheticlimb 12 to slide through the opening 74 (FIG. 4) during the adjustmentprocess.

With reference now to FIGS. 12, 13, 13A and 13B, an alternativeembodiment of an alignment device 800 in accordance with the principlesof the present invention is shown, where like numerals are used toidentify like parts. In this embodiment, an extendable and retractablepositioning mechanism 802, arranged as a linkage assembly, is providedto move a pylon-shaped prosthetic limb 804 through the forward andrearward angular movements as described in detail above. The positioningmechanism 802 includes a pair of shafts 806 connected to a pair offlanges 808 provided on a mounting base 810. The shafts 806 extendacross the length of the mounting base 810 and are aligned generallyparallel to the anterior-posterior plane.

A generally T-shaped coupling member 812 is slidably mounted on theshafts 806 for extended and retracted movement along the shafts.Coupling member 812 includes a pair of unthreaded bores 814 (one shownin dash lines in FIGS. 13A and 13B) that slidably receive the pair ofshafts 806. Coupling member 812 includes a hinge connection 816 whichmay be U-shaped, and thus, coupling member 812 is rotatably connectedwith a hinge connection 818 formed on an upper end of a limb supportmechanism 820. As best understood with reference to FIG. 13, limbsupport mechanism 820 terminates in a socket 822 that is received withinan adaptor 824 mounted on the upper end of the pylon-shaped prostheticlimb 804. Four (4) set screws 826 are provided to securely mount theadaptor 824 to the socket 822.

As best understood with reference to FIGS. 12 and 13, a limb receivingmember 828 is rotatably supported between the pair of side plates 30through a pair of fasteners 830. The ends of the limb receiving member828 are located in bushings 834 (FIG. 12), for example nylon bushings,that extend through bores 836 (one shown in dash in FIG. 13) formed at alower end of the side plates 30. Limb receiving member 828 includes aspherically-shaped-bushing 838 that is mounted within aspherically-shaped socket 840 of the rotatable limb receiving member828. Bushing 838 may be snap-fit into the socket 840 and is held inplace by a locking ring 842 that threadably engages with the rotatablelimb receiving member 828. The rotatable limb receiving member 828includes an opening extending through the member 828 for slidablyreceiving the prosthetic limb 804.

Further referring to FIGS. 12-13, a locking mechanism 846 is mountedwithin the mounting base 810 that is operable to engage gear teeth 848formed on an upper surface of the coupling member 812 to prevent slidingmovement of the coupling member 812 on the pair of shafts 806. Lockingmechanism 846 includes a rack gear support 850 having a top wall 852 anda pair of opposite flanges 854 that depend from the top wall 852 todefine a rack gear receiving recess 856. A rack gear 858 is positionedbetween the pair of flanges 854 in the recess 856 so that the rack gear858 is movable in opposite vertical directions, but is prevented frommoving in a horizontal direction by the pair of flanges 854. The rackgear 854 includes gear teeth 860 that are operable to engage the gearteeth 848 formed on the coupling member 812 when the rack gear 858 islowered into engagement with the coupling member 812 as described indetail below.

The locking mechanism 846 further includes a pair of spaced cam plates862 that extend on opposite longitudinal sides of the rack gear 858 andare mounted to a button actuator 864. The cam plates 862 and buttonactuator 864 are spring-biased relative to the rack gear support 850through a spring or other suitable biasing member 866. The pair of camplates 862 include a series of cam apertures 868 that receive pins 870extending from opposite longitudinal sides of the rack gear 858.

As shown in FIG. 13A, the cam plates 862 are biased to cause the rackgear 858 to engage the coupling member 812 to prevent sliding movementof the coupling member 812 on the pair of shafts 806. Upon manualdepression of the button actuator 864 as shown in FIG. 13B, the camplates 862 are translated relative to the rack gear support 850 to causethe rack gear 858 to raise vertically in the receiving recess 856 andout of engagement with the coupling member 812.

As those of ordinary skill in the art will readily appreciate, thebutton actuator 864 is easily accessible for manual actuation by thewearer. As the button 864 is manually depressed, the rack gear 858retracts, i.e., raises vertically, within the recess 856 and the weareris then free to set the angular alignment of the prosthetic limb 804 toa comfortable setting. Thereafter, the button actuator 864 is releasedand the rack gear 858 is then forced into engagement with the couplingmember 812 to lock and set the angular position of the prosthetic limb804 as desired by the wearer.

With reference now to FIGS. 14 and 15, an alignment device 900 inaccordance with yet another alternative embodiment of the presentinvention is illustrated. An extendable and retractable positioningmechanism 902, arranged as a linkage assembly, is provided to move theprosthetic limb (not shown) through forward and rearward angularmovements as desired by the wearer. The positioning mechanism 902includes a pair of shafts 904 (one shown in FIG. 14) connected to a pairof flanges 906 provided on a mounting base 908. The shafts 904 extendacross the length of the mounting base 908 and are aligned generallyparallel to the anterior-posterior plane.

A generally T-shaped coupling member 910 is slidably mounted on theshafts 904 for extended and retracted movement along the shafts 904.Coupling member 910 includes a pair of unthreaded bores 911 thatslidably receive the pair of shafts 904, and a slotted or keyed shaft912 that is threadably connected to and extends from the coupling member910 in a direction generally parallel to the shafts 904. The slottedshaft 912 includes multiple annular discs 914 that extend radiallyoutwardly from the shaft 912 to define locking slots 916 between eachpair of the discs 914. Coupling member 910 further includes a hingeconnection 918, which may be U-shaped, to rotatably connect the couplingmember 910 with a hinge connection 920 formed on an upper end of a limbsupport mechanism 922 as described in detail above.

Further referring to FIGS. 14 and 15, a locking mechanism 924 is mountedwithin the mounting base 908 that is operable to engage the slottedshaft 912 extending from the coupling member 910 to prevent slidingmovement of the coupling member 910 on the pair of shafts 904. Inparticular, locking mechanism 924 includes a spring-biased locking plate926 that is positioned to move in a transverse direction relative to theslotted shaft 912 of the coupling member 910. The locking plate 926includes an enlarged aperture 928 having a diameter greater than that ofthe annular discs 914 formed on the slotted shaft 912, and a smalleraperture 930 communicating with the enlarged aperture 928 that has adiameter less than that of the annular discs 914. The locking plate 926is mounted to or integral with a button actuator 932 so that the lockingplate 926 is spring-biased relative to the mounting base 908 through aspring or other suitable biasing member 934.

As shown in FIG. 15, the locking plate 926 is biased to cause thelocking plate 926, and in particular the smaller aperture 930, to engagebetween a pair of the annular discs 914 on the slotted shaft 912 toprevent sliding movement of the coupling member 910 on the pair ofshafts 904. Upon manual depression of the button actuator 932, thelocking plate 926 is translated relative to the slotted pin 912 so thatthe enlarged aperture 928 is moved in registry with the slotted pin 912.In this released position, the coupling member 910 is free to slidablymove along the pair of shafts 904 to change the angular position of theprosthetic limb (not shown).

As those of ordinary skill in the art will readily appreciate, thebutton actuator 932 is also easily accessible for manual actuation bythe wearer. When the button 932 is manually depressed, the slotted shaft912 is disengaged from the locking plate 926, and the wearer is thenfree to set the angular alignment of the prosthetic limb (not shown) toa comfortable setting. Thereafter, the button actuator 932 is releasedand the locking plate 926 is then moved into engagement with the slottedpin 912 to prevent the coupling member 910 from slidably moving on thepair of shafts 904 to lock and set the angular position of theprosthetic limb (not shown) as desired by the wearer.

While the present invention has been illustrated by a description ofvarious embodiments and while these embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The invention in its broader aspects istherefore not limited to the specific details, representative apparatusand method, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thespirit or scope of applicant's general inventive concept.

Having described the invention, what is claimed is:
 1. An alignmentdevice for a below-the-knee prosthetic lower leg adapted to beoperatively connected to a prosthetic foot, comprising: a mountingmechanism having a base and a pivotal connection and being configured tobe operatively connected to the below-the-knee prosthetic lower legthrough the pivotal connection proximate an upper end of the prostheticlower leg, the pivotal connection being movable in a path relative tothe base so that the prosthetic lower leg is adapted to move angularlyin an anterior-posterior plane relative to the base; and an extendableand retractable positioning mechanism operatively connected to themounting mechanism and configured to be operatively connected to theprosthetic lower leg, whereby the positioning mechanism is adapted toangularly align the prosthetic lower leg in the anterior-posterior planeupon extension or retraction of the positioning mechanism.
 2. Thealignment device of claim 1 wherein the positioning mechanism isextendable and retractable at least partially in a generally lineardirection.
 3. The alignment device of claim 1 further including abelow-the-knee prosthetic lower leg operatively connected proximate anupper end thereof to the mounting mechanism.
 4. The alignment device ofclaim 3 further including a prosthetic foot operatively connected at alower end of the prosthetic lower leg.
 5. The alignment device of claim1 further including a prosthetic socket operatively connected to themounting mechanism.
 6. The alignment device of claim 1 wherein thepositioning mechanism comprises a turnbuckle assembly.
 7. The alignmentdevice of claim 1 wherein the positioning mechanism comprises ahydraulic actuator.
 8. The alignment device of claim 1 wherein thepositioning mechanism comprises an electric actuator.
 9. The alignmentdevice of claim 1 wherein the positioning mechanism comprises a linkageassembly including a threaded screw and a coupling member threadablymounted on the screw and operatively connected to the prosthetic lowerleg.
 10. The alignment device of claim 1 wherein the positioningmechanism comprises a linkage assembly including a shaft and a couplingmember slidably mounted on the shaft and operatively connected to theprosthetic lower leg.
 11. The alignment device of claim 10 furthercomprising a locking mechanism associated with the coupling member andoperable to prevent sliding movement of the coupling member on theshaft.
 12. The alignment device of claim 11 wherein the lockingmechanism comprises a rack gear having a plurality of teeth operable toengage a plurality of teeth formed on the coupling member.
 13. Thealignment device of claim 11 wherein the locking mechanism comprises alocking plate operable to engage a slotted pin associated with thecoupling member.
 14. The alignment device of claim 10 further includingat least one inflatable bladder member operable to move the couplingmember along the shaft.